题干

2017年8月,中国航天科工集团正在论证研制的“最高时速 4000 公里”高速飞行列车在网络上“刷屏”,被网友称为“飞铁”,也引发了对“北京到上海约半小时”的未来憧憬。若已知北京到,上海的铁路长度约为 1300 公里,下列说法正确的是(   )

A:北京到上海的铁路长度约为 1300 公里指的是位移的大小

B:由题中数据可估算出“飞铁”从北京到上海的平均速度

C:时速 4000 公里,是“飞铁”从北京到上海的平均速率

D:时速 4000 公里,是“飞铁”从北京到上海的最大速率

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答案(点此获取答案解析)

D

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阅读理解

    With the development of our society, cell phones have become a common part in our lives. Have you ever run into a careless cell phone user on the street? Maybe they were busy talking, texting or checking updates on We Chat without looking at what was going on around them. As the number of this new “species” of human has kept rising, they have been given a new name-phubbers (低头族).

    Recently a cartoon created by students from China Central Academy of Fine Arts put this group of people under the spotlight. In the short film, phubbers with various social identities (身份) bury themselves in their phones. A doctor plays with his cell phone while letting his patient die, a pretty woman takes a selfie (自拍) in front of a car accident site, and a father loses his child without knowing about it while using his mobile phone. A chain of similar events finally leads to the destruction of the world.

    Although the ending of the film sounds unrealistic, the damage phubbing can bring is real. Your health is the first to bear the effect and result of it. “Always bending your head to check your cell phone could damage your neck,” Guangming Daily quoted doctors' words. “The neck is like a rope that breaks after long-term stretching.” Also, staring at cell phones for a long time will damage your eyesight gradually, according to the report.

    But that's not all. Being a phubber could also damage your social skills and drive you away from your friends and family. When getting together with family or friends, many people prefer to play their cell phones while others are chatting happily with each other and this creates a strange atmosphere, Qilu Evening News reported.

    It can also cost your life. There have been lots of reports on phubbers who fell to their death, suffered accidents, and were robbed of their cell phones in broad daylight.